The invention relates to a device for removing fluid from a container which holds gas and which has, in the area of a collecting point for fluid, an extraction connection which may be connected to a collecting container by way of an extraction line, which container may be connected by way of a compensating line to a compensating connection mounted on the container, which compensating connection is different from the extraction connection.
When containers holding gas are used in hydraulic circuits, oil is regularly fed to the gas side of the container, and accordingly fouling with oil occurs on the gas side. The fluid involved may also to some extent include an abrasive substance such as one deriving from movable rubber seals or the like. In addition, the fluid is regularly displaced by the operating gas. If it is desired to extract the fluid in question from the container, one in the form of a piston-type accumulator, for example, especially from the gas side of the container, the entire hydraulic system generally has to be shut down for a lengthy period, or at least the part of the system including the piston-type accumulator to be serviced and to be cleaned. In addition to the protracted system downtime, precise safety regulations must be adhered to, something which on the whole makes the servicing process elaborate and cost-intensive. The conventional servicing equipment, which optionally allows refilling of the gas side of the container with an operating gas, is structurally bulky and difficult to handle.
DE 297 22 504 U discloses a container for gaseous media, especially a large-volume pipeline with an inlet connection and an outlet connection, and with a vent connection and drain connection, the inlet connection and the outlet connection being designed simultaneously as vent and drain connections. The inlet connection comprises two inlet pipes which lead from a side inlet connection of the container in an arc to a high point in the interior of the container, the outlet connection comprising two outlet pipes which extend from a low point in the interior of the container in an arc to a side outlet connection of the container. Conventional containers, generally in the form of large-volume pipelines, are usually classified by general regulations as systems requiring monitoring, ones which are subject to strength and tightness testing with water, identified by the term water pressure testing, before being placed in service.
Such water pressure testing requires, in addition to the customary inlet and outlet connections provided for gas, also separate vent and drain connections at the high point and low point of the container, on its exterior wall. The conventional solution may dispense with separate vent and drain connections for water filling free of air, otherwise previously customary in the state of the art, so that complete discharge of water, as well as largely emission-free charging with natural gas, can be achieved, something which otherwise is partly responsible, especially in the form of methane losses, for enlargement of the ozone hole. Use of the conventional container as servicing unit for other containers is neither provided nor possible.
On the basis of this state of the art the object of the invention is to make available a compact fluid removal device as servicing unit, a device which may be connected to and again separated from the container after very short downtimes, in order distinctly to reduce the overall servicing time and the accompanying servicing costs. The object as formulated in these terms is achieved with a device having the features specified in claim 1.
The device is operated in such a way that, after being connected on the basis of the prevailing pressure differences between the container and the collecting container of the device, the fluid, which optionally may contain gas, is removed from the container and transferred to the collecting container. The collecting container then permits preferably a process of settling of the components of the fluid, in particular in the form of fouled fluid, it being possible for the gas components to flow back by way of the compensating line and compensating connection to the gas side of the container. As a result a sort of closed cycle is established, one which permits continuous operation of the device without hampering the oil removal process as a result of undesired pressure rises or the like. Since the compensating connection is in any event present with every container used for a gas refilling process, all that the container requires in addition is installation at a deep point in the container of an extraction connection different from the compensating connection, the fluid containing the gas being collected at the extraction connection. The device claimed for the invention can be quickly connected to and disconnected from the container by quick-release coupling equipment, so that the extraction process [proceeds] very quickly and the length of time that the device is shut down is quite limited. A compact design for the entire device can be achieved in particular when an oil collecting container of quite small dimensions is used. Furthermore, as compared with conventional solutions, only a small loss of gas occurs on the gas side of the container since dissolved nitrogen accrues only in the fluid, which is present especially in the form of oil, and concentrated or compressed nitrogen is found only in the residual gas area of the collecting container in terms of the only gas loss for the container.
Various advantageous embodiments are the object of the dependent claims.
Hereinafter the device according to the invention is to be explained in greater detail relative to two exemplary embodiments.